Can a sweet potato constipate you and are they fattening or healthy food?

Big picture: Whole societies have lived primarily on sweet potatoes. Don't let anybody give you a hard time if you like them. You do need to get with a sensible physician if you're chronically constipated as you indicate you are. If fiber in the diet and plenty of water don't get things going, checks for hypothyroidism, porphyria and even mild hirschsprung's are appropriate.